Longstanding issue with IOG + Predbat around midnight

[PianSom]

I am on Intelligent Octopus Go, which means that my low rate starts at 11.30pm. For a long time (many months, possible forever) Predbat seems not keen to acknowledge this, and does some discharging between 11.30pm and midnight.

This is especially noticeable today, a low solar generation combined with a high usage day. The plan below shows the battery being emptied by around 10pm, and then Predbat sceduling a charge and discharge cycle in that half hour, before reverting to more expected, rational behaviour.

I am at a loss to work out what to change to address this. Any suggestions?